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Posted at 07:30 AM ET, 03/05/2013

D.C. area forecast: Heavy, wet snow likely tonight into Wednesday, significant accumulations

Update, 7:30 a.m.: Winter storm warnings have been posted for Loudoun, Frederick, and Fauquier counties and to the west for snow accumulation of 10 to 14 inches between tonight at 6 p.m. and midnight Wednesday/Thursday morning. We suspect these warnings will be expanded eastward later today.

EXPRESS FORECAST

Today: Increasing clouds. 41-46. | Tonight: Rain/snow. 31-35. | Tomorrow: Heavy wet snow, possibly mixing with rain. 32-38.

TODAY'S DAILY DIGIT

A somewhat subjective rating of the day’s weather, on a scale of 0 to 10


Dreary day with colder-than-normal temps probably should be a “4”, but I added one for the snow excitement looming. Get the Digit on Twitter| Discuss on Facebook

SNOW POTENTIAL INDEX

A daily assessment of the potential for *accumulating* snow for the next week on a 0-10 scale. More info


SPI: 8+ (↑) .- While still some challenges on temperatures, the prospects for the biggest snow in 2+ years are promising Get the SPI on Twitter | Discuss on Facebook

FORECAST IN DETAIL


The Snowquester is coming with its fervent attempt to make a dent in our snow deficit. This is easily the biggest snow threat we’ve seen over the past two winters. The main precipitation starts tonight as a rain/snow mix in most areas which transitions to a heavy, wet snow from west to east early Wednesday. Significant snow accumulations of 3-8 inches are likely (and even more, 6-12 inches, west of the Beltway). Snow ends Wednesday night with a gradual warming trend Thurday into the weekend.

Today (Tuesday): Clouds increase during the course of the day, which should hold temperatures colder-than-normal for another day. Highs in the low-to-mid 40s with light and variable winds. There is 20 percent chance of light precipitation (rain or mix) during the late afternoon especially west and southwest of the city but significant commuting problems are not expected. Confidence: Medium-High

Tonight: Precipitation begins - for most spots - between 7 and 10 p.m.as rain or a wintry mix. This precipitation gradually transitions to more snow as the night wears on. The far western suburbs may get all snow from the onset. Accumulations by morning could range from 3-6” in the far western suburbs to 1-3” in the city by rush hour Wednesday morning. Temperatures should be in the low-to-mid 30s. Winds start picking up after midnight increasing to 15-25 mph and gusty from the northeast. Confidence: Low-Medium

For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend...

Tomorrow (Wednesday): Heavy wet snow is likely which could mix with rain at times along and east of I-95. Precipitation should continue through the day along with winds 20-25 mph with higher gusts. Temperatures hold in the 30s so those winds make it feel quite nasty out there combined with the wet snow. Visibilities are frequently reduced as well.

Also be wary and prepared for power outages as high winds and heavy wet snow can snap tree branches and down power lines, especially in locations where upwards of 6 inches of snow fall.

What about the roads? When snow falls heavily enough, it will stick even if temperatures are a little above freezing creating hazardous conditions. But the most persistently bad conditions are likely in the western suburbs. In the city and east, snow may not stick as well (except during heavier bursts). Confidence: Medium


Tomorrow night: Snow ends during the evening to overnight hours with temperatures easing down close to 32. The western suburbs should see freezing to sub-freezing conditions so look out out for re-freezing and black ice. Those pesky winds are still blowing at 15-20 mph with higher gusts.

Total accumulations are shown above. Please keep in mind that temperatures around the District and east could very well stay above freezing for most or all of the event- meaning heavy wet snow will compact and melt some along the way. Confidence: Medium

A LOOK AHEAD

Thursday features partly to mostly cloudy skies, breezy conditions, and highs in the low to mid 40s to keep the melting and recovery process going. Partly cloudy skies Thursday night with temperature dipping back below freezing from the mid-20s to low 30s. This means things re-freeze and untreated areas could be tricky. Confidence: Medium-High

Friday should feature mostly sunny skies with temperatures surging into the middle to upper 40s again to keep the melting going. Friday night is partly cloudy with lows in the upper 20s to low 30s again, but they should be marginally warmer than Thursday night. Confidence: Low-Medium

The weekend continues to be dry with partly to mostly sunny skies and warming temperatures. Look for upper 40s to low 50s for Saturday highs and the middle 50s for Sunday. Lows Saturday night should range through the 30s. Confidence: Low-Medium

By  |  07:30 AM ET, 03/05/2013

Categories:  Forecasts

 
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